Process and apparatus for treating heterogeneous waste to provide a homogeneous fuel

Abstract

Apparatus and method are described for processing waste into a clean fuel. The waste comprises organic and inorganic portions. A float tank is filed with a liquid, e.g., water, of a selected depth. The waste is introduced into the liquid and separates into its organic portion, which floats near the surface of the liquid, and into its inorganic portion, which falls towards the bottom of the tank. The liquid depth is selected to be sufficiently large to permit the separation of the organic and inorganic portions. Then the organic and inorganic portions are removed. Sufficient liquid is extracted from the separated organic portion to provide the clean fuel. The fuel, illustratively, is formed as pellets. In a further aspect of this invention, further liquid is added to the separated organic portion to form a mixture thereof, which is pulped to provide a slurry thereof of a relatively high moisture content. Liquid is extracted by mechanical means, e.g., belt and/or screw presses, from the slurry to provide the clean fuel of a relatively low, homogeneous liquid content.

It is claimed: 
     
       1. A method for processing waste into a clean fuel, the waste comprising an organic portion and an inorganic portion, the fuel comprising primarily the organic portion, said method comprising the steps of: a) maintaining a body of liquid of a selected depth within a float tank;   b) introducing the waste into the float tank and the body of liquid therein, the liquid body having a bottom and an upper surface, the liquid depth being selected to be sufficiently large to permit the separation of the waste into the organic and inorganic portions;   c) cleaning the waste within the liquid body by separating the inorganic portion from the organic portion, the organic portion floating to the upper surface of the liquid body, the inorganic portion settling towards the bottom of the liquid body, whereby the inorganic portion is physically separated from the floating organic portion;   d) removing the cleaned organic portion from the liquid surface and the inorganic portion from the bottom; and   e) extracting sufficient liquid from the cleaned, separated organic portion to provide the clean fuel.   
     
     
       2. The method of claim 1, further comprising the step of shredding the waste, before introducing it into the liquid body, into components of given dimensions. 
     
     
       3. The method of claim 1, further comprising the steps of adding further liquid to the separated organic portion to form a mixture thereof and pulping the mixture to provide a slurry thereof of a relatively high moisture content, step e) extracts sufficient liquid from the slurry to provide the clean fuel of a sufficiently low, homogeneous liquid content to permit efficient burning of the fuel. 
     
     
       4. The method of claim 3, wherein step e) includes the step of mechanically extracting liquid from the slurry. 
     
     
       5. The method of claim 4, wherein the step of mechanically extracting removes the majority of moisture by weight from the slurry. 
     
     
       6. The method of claim 3, further comprising the step of forming the clean fuel of the sufficiently low, homogeneous liquid content into pellets thereof to permit efficient burning of the fuel. 
     
     
       7. The method of claim 4, wherein step e) includes the step of thermally extracting liquid from the slurry. 
     
     
       8. The method of claim 1, wherein the liquid is water. 
     
     
       9. The method of claim 1, wherein the removed inorganic portion comprises ferrous metals, nonferrous metals and silicon products and there further comprises the step of subjecting the removed inorganic portion to a magnetic field to extract therefrom the ferrous metals and leaving any remaining nonferrous metals. 
     
     
       10. The method of claim 9, further comprising the steps of crushing and then screening the remaining nonferrous metals and silicon products to thereby separate these materials. 
     
     
       11. Apparatus for processing waste into a clean organic material, the waste comprising organic and inorganic portions, said apparatus comprising: a) a separation tank for separating the waste into the organic and inorganic portions, said separation tank having a bottom and a top opening, said separation tank containing a body of liquid, the liquid body including a top surface and a bottom portion disposed adjacent said bottom of said tank;   b) means for introducing the waste through said top opening into the liquid body;   c) said separation tank having sufficient dimensions to contain a sufficient volume of the liquid body to establish a liquid depth as measured from said bottom of said separation tank to the liquid surface to permit the waste to separate into its organic portion, which floats at the liquid surface, and into its inorganic portion, which settles to bottom portion of the liquid body;   d) means for removing the separated organic portion from the liquid surface; and   e) means for extracting liquid from the removed organic portion to provide the clean, dry organic material.   
     
     
       12. The waste processing apparatus as claimed in claim 11, wherein the clean organic material is a fuel and said liquid extracting means extracts sufficient liquid from the organic portion to provide the clean fuel of a sufficiently low water content to be burned. 
     
     
       13. The waste processing apparatus as claimed in claim 11, wherein there is further included means for shredding the waste into particles of limited dimension, said introducing means conveying the shredded waste particles into the liquid body. 
     
     
       14. The waste processing apparatus as claimed in claim 13, wherein said shredding means fixes the limited dimension of the particles and reshreds any of the waste which exceed the limited dimension. 
     
     
       15. The waste processing apparatus as claimed in claim 11, wherein said separation tank has opposing side walls which slant towards each other so that said bottom is of a lesser dimension than that of said opening, whereby the inorganic portion is guided to said bottom of said separation tank. 
     
     
       16. The waste processing apparatus as claimed in claim 11, wherein said organic portion removing means comprises means immersed within the liquid body at a shallow depth from the liquid surface for directing pressurized jets of the liquid in a first direction to transport the separated organic portion towards one end of said separation tank. 
     
     
       17. The waste processing apparatus as claimed in claim 16, wherein said organic portion removing means further comprises means disposed at said one end of said separation tank for removing the transported organic portion from the liquid surface and conveying it to said liquid extracting means. 
     
     
       18. The waste processing apparatus as claimed in claim 16, wherein there is further included means disposed at said bottom of said separation tank for removing the settled inorganic portion from said separation tank. 
     
     
       19. The waste processing apparatus as claimed in claim 18, wherein said separation tank comprises a port disposed adjacent said bottom of said separation tank and at another end thereof opposite said one end thereof, said inorganic portion removing means conveys the settled inorganic portion in a second direction opposite to said first mentioned direction towards said port, whereby the settled inorganic portion is removed through said port and from said separation tank. 
     
     
       20. The waste processing apparatus as claimed in claim 16, wherein said organic portion removing means further comprises second means immersed with the liquid body at a deeper depth from the liquid surface for directing second pressurized jets of the liquid in a second direction opposite to said first direction whereby a circulating current of the liquid is established within the liquid body. 
     
     
       21. The waste processing apparatus as claimed in claim 20, wherein said separation tank comprises a port disposed at another end opposite said one end and at said bottom thereof for permitting the settled inorganic portion to be removed therethrough from said separation tank, and a baffle disposed adjacent said another end and extending from the liquid surface to a depth deeper than the circulating current of the liquid to prevent the removal of the organic portion through said port. 
     
     
       22. The waste processing apparatus as claimed in claim 16, wherein said jets directing means comprises at least one nozzle with a plurality of jet openings spaced along the length thereof, and a pump for pressurizing and providing the liquid to said nozzle. 
     
     
       23. The waste processing apparatus as claimed in claim 16, wherein there is further included means for capturing the liquid escaping from said waste processing apparatus and for recirculating it to said jets directing means. 
     
     
       24. The waste processing apparatus as claimed in claim 23, wherein said capturing means further includes means for removing impurities in the recaptured liquid before recirculating it to said jets directing means.